86Box/src/sound/snd_opl_backend.c

/* Copyright holders: Sarah Walker, SA1988
   see COPYING for more details
*/
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "86box.h"
#include "nukedopl.h"
#include "sound.h"
#include "snd_opl_backend.h"
#include "cpu.h"
#include "mem.h"


int opl_type = 0;


static struct
{
    struct opl3_chip opl3chip;
    int addr;
    int timer[2];
    uint8_t timer_ctrl;
    uint8_t status_mask;
    uint8_t status;
    int is_opl3;

    void (*timer_callback)(void *param, int timer, uint64_t period);
    void *timer_param;
} opl[2];


enum
{
    STATUS_TIMER_1 = 0x40,
    STATUS_TIMER_2 = 0x20,
    STATUS_TIMER_ALL = 0x80
};

enum
{
    CTRL_IRQ_RESET   = 0x80,
    CTRL_TIMER1_MASK = 0x40,
    CTRL_TIMER2_MASK = 0x20,
    CTRL_TIMER2_CTRL = 0x02,
    CTRL_TIMER1_CTRL = 0x01
};


void
opl_init(void (*timer_callback)(void *param, int timer, uint64_t period), void *timer_param, int nr, int is_opl3)
{
    opl[nr].timer_callback = timer_callback;
    opl[nr].timer_param = timer_param;
    opl[nr].is_opl3 = is_opl3;

    opl[nr].opl3chip.newm = 0;
    OPL3_Reset(&opl[nr].opl3chip, 48000);
}


void
opl_status_update(int nr)
{
    if (opl[nr].status & (STATUS_TIMER_1 | STATUS_TIMER_2) & opl[nr].status_mask)
	opl[nr].status |= STATUS_TIMER_ALL;
    else
	opl[nr].status &= ~STATUS_TIMER_ALL;
}


void
opl_timer_over(int nr, int timer)
{
    if (!timer) {
	opl[nr].status |= STATUS_TIMER_1;
	opl[nr].timer_callback(opl[nr].timer_param, 0, opl[nr].timer[0] * 4);
    } else {
	opl[nr].status |= STATUS_TIMER_2;
	opl[nr].timer_callback(opl[nr].timer_param, 1, opl[nr].timer[1] * 16);
    }

    opl_status_update(nr);
}


void
opl_write(int nr, uint16_t addr, uint8_t val)
{
    if (!(addr & 1)) {
	opl[nr].addr = (int)OPL3_WriteAddr(&opl[nr].opl3chip, addr, val) & 0x1ff;
	if (!opl[nr].is_opl3)
		opl[nr].addr &= 0xff;
    } else {
	OPL3_WriteRegBuffered(&opl[nr].opl3chip, (uint16_t) opl[nr].addr, val);
	if (opl[nr].addr == 0x105)
		opl[nr].opl3chip.newm = opl[nr].addr & 0x01;

	switch (opl[nr].addr) {
		case 0x02:	/*Timer 1*/
			opl[nr].timer[0] = 256 - val;
			break;
		case 0x03:	/*Timer 2*/
			opl[nr].timer[1] = 256 - val;
			break;
		case 0x04:	/*Timer control*/
			if (val & CTRL_IRQ_RESET) {	/*IRQ reset*/
				opl[nr].status &= ~(STATUS_TIMER_1 | STATUS_TIMER_2);
				opl_status_update(nr);
				return;
			}
			if ((val ^ opl[nr].timer_ctrl) & CTRL_TIMER1_CTRL) {
				if (val & CTRL_TIMER1_CTRL)
					opl[nr].timer_callback(opl[nr].timer_param, 0, opl[nr].timer[0] * 4);
				else
					opl[nr].timer_callback(opl[nr].timer_param, 0, 0);
			}
			if ((val ^ opl[nr].timer_ctrl) & CTRL_TIMER2_CTRL) {
				if (val & CTRL_TIMER2_CTRL)
					opl[nr].timer_callback(opl[nr].timer_param, 1, opl[nr].timer[1] * 16);
				else
					opl[nr].timer_callback(opl[nr].timer_param, 1, 0);
			}
			opl[nr].status_mask = (~val & (CTRL_TIMER1_MASK | CTRL_TIMER2_MASK)) | 0x80;
			opl[nr].timer_ctrl = val;
			break;
	}
    }
}


uint8_t
opl_read(int nr, uint16_t addr)
{
    if (!(addr & 1))
	return (opl[nr].status & opl[nr].status_mask) | (opl[nr].is_opl3 ? 0 : 0x06);

    if (opl[nr].is_opl3 && ((addr & 3) == 3))
	return 0x00;

    return opl[nr].is_opl3 ? 0 : 0xff;
}


void
opl2_update(int nr, int32_t *buffer, int samples)
{
    OPL3_GenerateStream(&opl[nr].opl3chip, buffer, samples);
}


void
opl3_update(int nr, int32_t *buffer, int samples)
{
    OPL3_GenerateStream(&opl[nr].opl3chip, buffer, samples);
}